1. Dr Amy Stebbings The Chest and Internal Medicine Clinic, Singapore
The Effect of Forest Fires in 2015 on Asthma and Comparison with a Control Group in 2016

2. Background
Singapore experienced increased air pollution (Haze) for 2 months in arising from regional forest fires.
Aim: to investigate the effect of this on respiratory disease, particularly asthma
Previous studies (Respirology 2000 Jun: 5(2): ) demonstrated minimal effect, with no increase in hospitalisation

4. Aim
To describe the effect of air pollution induced by regional forest fires on respiratory disease, with special attention to asthma, in 2015
and
to compare it with a similar period in 2016

5. Average Hourly PSI (Aug-Nov) 2015 (Haze) vs 2016 (No haze)

6. Average Hourly PSI
p-value <0.0001, statistically significant

7. Calculation of the PSI Sub-indices as defined by the breakpoints
Equation used for calculation

8. Method -Prospective study
-All patients who visited a respiratory clinic in Singapore
-Over a 2-month period: September-October 2015 (Haze).
-Data collected: Asthma exacerbations/hospitalisations, Asthma Control Test (ACT) scores of asthmatic patients, spirometry, adjustments in medications.
-Comparison was made retrospectively with a control group in September-October (No Haze)

9. Table 1: Demographics and Spirometry: Case (Haze 2015) vs Control (no haze 2016)
Categories
Case (haze 2015)
Control ( no haze 2016)
p-value
NS (not significant)
Mean age (years)
46.08
47.34
0.665 NS
Age range (years)
16-93
5-94 NA
Sex (% male)
33.33
33.82
Mean FEV1 asthmatics(%)
91.9
91.8
0.974
Mean FVC asthmatics (%)
102.6
99.9
0.404
Mean FEV1 ratio asthmatics (%)
76.3
79.1
0.0979

10. Ethnicity of patients Chinese 18 41 0.102 NS 8 0.233 Indian 11 0.319 5
All patients (n=74) 2015 (Haze)
All patients (n=125) 2016 (No Haze)
p-value
Significance (p<0.01)
Asthmatics (n=51) 2015 (Haze)
Asthmatics (n=64)
2016 (No Haze)
Chinese 18 41
0.102 NS 8
0.233
Indian 11
0.319 5 7
0.371
Malay 2 3
0.448
0.295
Others 6
0.171
0.0655
Caucasian 40 64
0.348 31 34
0.0162

11. Other diagnoses (Non-asthmatics)
Diagnosis
Number of non-asthmatics (2015)
Number of non-asthmatics (2016)
p-value
Significance
Hypercholesterolaemia 3
0.0901 NS
Tuberculosis 1 5
0.145
Pneumonia 2
0.316
Pulmonary Embolism
0.444
COPD
Bronchitis 4 9
0.309
Bronchiectasis 7
Hypertension 6
0.0281 DM
Sinusitis
0.492
Others 11 26
0.149

12. A closer look: the asthmatics during the haze 2015
Total number of asthmatics: 51
47% experienced asthma exacerbation
5.4% vs 0.8% required hospitalisation (significant)
6.8% required an increase in Prednisolone (not significant, NS)
Mean ACT score 15.8 (range 7-25, SD 5.08) (NS)
Mean change in ACT from baseline was 7.1 (range 0-18, SD 4.75) (NS)

13. Table 2: Comparison of Asthma Exacerbations, Hospitalisations and Treatment, Case vs Control
% of total
Case (haze 2015)
Control ( no haze 2016)
p-value
Significance N 74
125
Asthma patients
51 (68.9%)
64 (51%)
0.007
p<0.01
Hospitalisation
4 (5.4%)
1 (0.8%)
0.022
p<0.05
Asthma exacerbation
21 (28.4%)
19 (15.2%)
0.013
Nebulisation
4 (5.41%)
5 (4%)
0.323 NS
Oral steroids
5 (6.8%)
8 (6.4%)
0.460
ACT change
7.1 (0-18)
6.7 (0-15)
0.825

14. Limitations of this study
Cohort based in a respiratory clinic at tertiary level, not community based
Assumption is that the patients were well controlled before the haze
Assumption the control group were well controlled
Larger numbers needed
Any confounding factors?

15. Conclusion
Forest fires significantly impacted the health of patients with respiratory disease, particularly asthmatics, as demonstrated by increase in hospitalisations and asthma exacerbations

16. References
Meteorological conditions, climate change, new emerging factors, and asthma and related allergic disorders. A statement of the World Allergy Organization. D’Amato et al, World Allergy organ J 2015 jul 14;8 (1):25
Asthma Control in the Asia-Pacific region : the Asthma Insights and reality in Asia-Pacific Study. Lai CK et al, J Allergy Clin Immunol 2003 Feb;111(2):263-8
An Evaluation of the British Columba Asthma Monitoring System (MCAMS) and PM2.5 Exposure Metrics during the 2014 Forest Fire Season. McLean KE et al, Int J Environ Res Public Health 2015 Jun 12;12(6):
Asthma Control in Adults in Asia Pacific. Zainuddin BM, et al, Respirology Nov 10950:579-86
Impact to lung health of haze from forest fires: the Singapore experience. Emmanuel SC. Respirology Jun;5(2):